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  Mutli-inheritance bug between python 2.7 and 3.7

When we have run a py3.7 code under py2.x or a py2.x code under 3.x ,if a class do mutli-inheritance from 2 parent and the 2 parents also got inheritance from same parent, the different way to handle inheritance chain between python 2 and 3 will cause some running time bug: Assume we got this sample program inheritTest.py : # Purpose: Test mutli-inheritance different between python2 and 3 # Author: Yuancheng Liu # Created: 2019/05/16 class A: def getVal(self): print("cal...

   PYTHON,PYTHON 3,INHERITANCE     2019-05-16 08:33:52

  Exit main thread and keep other threads running in C

In C programming, if using return in main function, the whole process will terminate. To only let main thread gone, and keep other threads live, you can use thrd_exit in main function. Check following code: #include #include #include int print_thread(void *s) { thrd_detach(thrd_current()); for (size_t i = 0; i < 5; i++) { sleep(1); printf("i=%zu\n", i); } thrd_exit(0); } int main(void) { ...

   C LANGUAGE,MULITHREAD,MAIN THREAD     2020-08-14 21:20:04

  Tips to improve JavaScript efficiency

Writing JavaScript code is tedious and error prone. You not only need to implement the necessary functions, but also need to ensure cross browser compatibility. This often causes the low efficiency of JavaScript developers. Here we recommend 12 tips you can benefit from. 1. Remove array element by index If we want to remove one element in an array, we can use splice. function removeByIndex(arr, index) { arr.splice(index, 1); } test = new Array(); test[0] = ’Apple’; test[1] = &rsq...

   JavaScript,Tips,Array     2013-07-27 20:50:40

  HTML5 Web Worker

Web Worker is a JavaScript multithreading solution provided by HTML5. we can put some compute intensive codes into Web Worker and it will not hang the user interface. 1. How to use Web Worker Web Worker's basic mechanism is to use Worker to load a JavaScript file to create a new thread in JavaScript's main thread. It will not block other thread's execution and will provide a data exchange interface between main thread and new thread : postMessage() and onmessage. Let's look at an example: //work...

   JavaScript,HTML,Web Worker     2012-12-02 06:25:00

  Write Your Own R Packages

Introduction A set of user-defined functions (UDF) or utility functions are helpful to simplify our code and avoid repeating the same typing for daily analysis work. Previously, I saved all my R functions to a single R file. Whenever I want to use them, I can simply source the R file to import all functions. This is a simple but not perfect approach, especially when I want to check the documentation of certain functions. It was quite annoying that you can’t just type ?func&n...

   DATA SCIENCE,R PROGRAMMING,DATA ENGINEERING     2019-10-19 07:20:52

  Highly efficient PHP code writing

Next are some tips for writing highly efficient PHP codes. They are described below: 0. Use single quote to replace double quote, this will be better since PHP will serach for variables in double quoted strings. Note, only echo can do this; 1. If we can define methods of a class as static, then do it. It will increase access speed by 4 times; 2. $row["id"] is 7 times faster than $row[id]; 3. echo is faster than print, and also use echo's multiple parameter format such as echo $str1,$str2 inst...

   PHP,Code writing,High efficient,Tips     2011-07-23 12:35:50

  Unfortunate Python

Python is a wonderful language, but some parts should really have bright WARNING signs all over them. There are features that just can't be used safely and others are that are useful but people tend to use in the wrong ways. This is a rough transcript of the talk I gave at my local Python group on November 15, with some of the audience feed back mixed in. Most of this came from hanging around the Python IRC channel, something I highly recommend. [update 2011-12-19: improved "array" cr...

   Python,Defects,Deprecated methods,Warning     2011-12-20 08:27:36

  How long does the heuristic cache of the browser actually cache?

Heuristic cache Heuristic caching is the default behavior of browser caching (i.e., for responses without Cache-Control), which is not simply "not caching", but implicitly caching based on the so-called "heuristic cache". HTTP is designed to cache as much as possible, so even if Cache-Control is not specified, the response will be stored and reused if certain conditions are met. This is called heuristic caching. HTTP/1.1 200 OK Content-Type: text/html Content-Length: 1024 Date: Tue, 22 Feb 2022 ...

   HEURISTIC CACHE,WEB DESIGN     2023-05-26 08:40:13

  Tips of Drafting an R Markdown Document

When presenting the data summary and exploratory analysis, we used to copy a lot of tables, charts from Rstudio to PowerPoint, which makes the presentation preparation painful. It becomes essential for data scientists to make use of better reporting tools, such as R markdown, Jupyter notebook to prepare the analysis presentation in a more efficient and organized way. Of course, we want this to be reproducible! In this post, I would like to share some tips of using the right tools to draw tables,...

   R PROGRAMMING     2020-11-01 23:09:45

  Run executable jar on double click on Windows

Normally after installing Java, there will be an association between .jar and the javaw.exe. This enables the executable jar to be opened on double click. You can check the association by going to Control Panel -> Programs -> Default Programs -> Associate a file type or protocol with a program. The default program of a file type can be changed in this dialog. However sometimes there are cases where the file association for .jar may be altered after a third party application instal...

   JAVA,WINDOWS,JAR,EXECUTABLE JAR     2016-05-12 03:05:04

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